Cristian Fogel [:cfogel] Reporter
	Description • 6 years ago

[Affected versions]:
- 63.0a1 (2018-07-31), 62.0b13;

[Affected platforms]:
- win 10x64, Ubuntu 16.04LTs, macOS 10.13.4

[Steps to reproduce]:
1. Launch Firefox;
2. Access the following link: https://rawgit.com/dadaa/3b73f847427025b51ba1ab7333013d0c/raw/77f3f0bb884875a179c3407f73bf8a8dd54751c9/doc_simple_animation.html
3. Open DevTools - Inspector tab;
4. Click and select the <ball delayed> class;
5. If not already toggle off the (inspector) 3pane tab;
6. In the inspector pick the Animations section;
7. Click on the Console tab;
8. Click on the Inspector tab.


[Expected result]:
The UI is displayed properly, nothing changed.

[Actual result]:
Some scale-segments are not properly hidden. 

[Regression range]:
pushlog url:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=380cf87c1ee3966dd94499942b73085754dc4824&tochange=1800b8895c08bc0c60302775dc0a4b5ea4deb310

[Additional notes]:
- attached screen recording with the issue;
- when 3-pane mode is enabled the issue doesn't seem to be reproducible;
- on some versions you need to repeat steps 7+8 a couple of times to force it.

	Cristian Fogel [:cfogel] Reporter
	Comment 1 • 6 years ago

mozregresion points out to the bug listed bellow, Matt can you take a look at it please? 
https://bugzilla.mozilla.org/show_bug.cgi?id=1371668

	Matt Woodrow (:mattwoodrow)
	Comment 2 • 6 years ago

This looks like an actual bug in devtools to me!

But 1371668 changed the timings of when we paint, so it's possible that we're displaying frames that we didn't previously.

The devtools code would have to be leaving the panel in a state where the animations tab is full width though and returning to the event loop in that state.

	Pascal Chevrel:pascalc (PTO until April 26)
	Comment 3 • 6 years ago

Wontfixing for current releases + esr not affected as the regression happened in 62.